High density DNA microarray technology has begin to revolutionize the way biological phenomena are described. An important component of this technology is its ability to provide a global gene expression molecular profile of specific cell types under normal or stimulated conditions. The Microarray Core will use standard 15,000 mouse gene microarrays to provide a detailed gene profiling of blood cell-based inflammatory response as well as generate custom microarrays of genes disrupted in our libraries of mutant ES cell clones. These custom arrays when added to the global 15,000 gene arrays will provide an efficient means to analyze and prioritize novel transcripts for further studies and develop a detailed molecular description of blood-oriented inflammation.